seminář studentů 2009 - J. Heyrovský Institute of Physical Chemistry

Transkript

Konferenční centrum
AV ČR v Liblicích
24. - 26. 4. 2013
Seminář studentů ÚFCH JH 2013
Sborník příspěvků
ze studentské konference konané
24.-26. dubna 2013
v Konferenčním centru AV ČR Liblicích
Seminar of Students of JHI 2013
Collection of abstracts
of all lectures given at the student conference
held on 24 -26 April 2013
in Conference Centre of the Academy of Sciences
of the Czech Republic in Liblice chateau
Seminář studentů ÚFCH JH 2013
Sborník příspěvků ze studentské konference
konané 24.-26. dubna 2013
v Konferenčním centru AV ČR Liblicích
Kolektiv autorů
Sestavila: Květa Stejskalová
Vydává: Ústav fyzikální chemie J. Heyrovského AV ČR, v.v.i. Dolejškova 2155/3,
182 23 Praha 8, Česká republika
Tisk: Ústav fyzikální chemie J. Heyrovského AV ČR, v.v.i. Dolejškova 2155/3,
182 23 Praha 8
Vydání: první
Náklad: 35 kusů
Místo a rok vydání: Praha, 2013
Publikace neprošla jazykovou úpravou
© Ústav fyzikální chemie J. Heyrovského AV ČR, v.v.i.
SEMINÁŘ STUDENTŮ ÚFCH JH 2013
PROGRAM 1. dne konference - středa 24.4.2013
Odjezd autobusem z parkoviště před ústavem ve 13:00 hodin.
Předpokládaný příjezd do Konferenčního centra AV ČR v zámku
v Liblicích okolo 14:00 hodiny.
Čas
Předsedající
Přednášející
Název
14:0015:25
Registrace a ubytování účastníků konference - v recepci
Od 15 hodin - občerstvení před zahájením konference
(káva, nápoje, zákusek - v 1. patře)
15:25
Zahájení konference „Seminář studentů ÚFCH JH 2013“
- prezentace studentů z kategorie I.
15:30
Jakub LANG (magisterské
studium, PřF UK, školitel
J. Pittner) kat I
AN AB INITIO INVESTIGATION OF THE
ISOMERIZATION OF BICYCLOBUTANE:
DESCRIPTION OF THE CONROTATORY AND
DISROTATORY STATES
Roman NEBEL
(bakalářské studium,
VŠCHT Praha
školitel P. Krtil) kat I
VYSOKOTLAKÁ SYNTÉZA FLUORESCENTNÍCH
A KATALYTICKY AKTIVNÍCH SULFIDŮ
16:10
Michaela RYBÁROVÁ
(magisterské studium, FBMI
ČVUT, školitel P. Španěl)
kat I
VÝVOJ METOD EXTRAKCE TĚKAVÝCH LÁTEK Z
BIOLOGICKÝCH VZORKŮ
16:30
Jan BOHUSLAV
VŠCHT Praha
školitelé P.Janda a H.
Tarábková) kat I
NANOČÁSTICOVÁ ELEKTRODA:
ELEKTROCHEMICKÉ A NANOMORFOLOGICKÉ
VLASTNOSTI Ni/HOPG ELEKTRODY PŘIPRAVENÉ
RŮZNÝMI METODAMI DEPONOVÁNÍ
15:50
Adéla
FRIDRICHOVÁ
PŘESTÁVKA
16:50
17:00
17:20
Milan
BOUŠA
17:40
Miloš VEČEŘA (bakalářské
studium, Přf UK; školitel
M. Lamač) kat I
SYNTÉZA KOMPLEXŮ PRVKŮ 4. SKUPINY
S CYKLOPENTADIENYL-KETIMIDOVÝMI
CHELATUJÍCÍMI LIGANDY
Kateřina JURKOVÁ
(bakalářské studium, PřF
UK, školitel M. Kalbáč) kat I
SINGLE-LAYER MOS2 AND ITS INTERACTION
WITH GRAPHENE
Pavel KOŠŤÁL
(bakalářské studium
MFF UK; šk. M. Fárník) kat I
STUDIUM DYNAMIKY FOTODISOCIACE
ZOBRAZOVACÍ METODOU IMAGING
PŘESTÁVKA
18:00
18:10
18:30
Pavla
CHLUBNÁ
18.50
Tomáš HODÍK (bakalářské
studium, VŠCHT Praha
školitel J. Pinkas) kat I
SWEET TITANOCENES AND FERROCENES
Vít SVOBODA
VŠCHT Praha, školitel
O.Votava) kat I
OVERTONOVÁ SPEKTROSKOPIE V
SUPERSONICKÝCH EXPANZÍCH
Jakub VIŠŇÁK
(I. ročník PGS, školitel J.
Pittner) kat I
AB INITIO VIBRATIONAL TRANSITION
CALCULATION BY THE NOMO/CI METHOD ON A
SIMULATED QUANTUM COMPUTER
19:10
Alan LIŠKA
(magisterské studium, PřF
UK, školitel J. Ludvík) kat I
ELECTROCHEMICAL REDUCTION OF STRUCTURALLY MODIFIED POLYNITROCALIX[4]ARENES
Ukončení prvního dne konference
19:30
VEČEŘE v RESTAURACI - začátek v 19:30
PROGRAM 2. dne konference - čtvrtek 25.4.2013
Čas
8:25
Předsedající
Přednášející
Název
Zahájení druhého dne konference - pokračují prezentace studentů kategorie I a II.
8:30
Matej ŠVAŇA
UK, školitel J. Pittner) kat I
STUDY OF DIRADICALS BY EXPLICITLY
CORRELATED MULTIREFERENCE COUPLED
CLUSTER METHODS
8:50
Jakub EDERER
UK, školitel P. Janda) kat I
MULTIKOMPONENTNÍ ANALÝZA VZORKU
POUŽITÍM VÍCEELEKTRODOVÉHO SYSTÉMU
Štěpánka LACHMANOVÁ
(I. ročník PGS,
školitelka M. Hromadová)
kat I
REDUCTION OF SELECTED BRANCHED
EXPANDED PYRIDINIUM CATIONS
Martina PARISOVÁ
(I. ročník PGS, školitel T.
Navrátil) kat I
CHARACTERIZATION OF BIOLOGICAL
MEMBRANE
Barbora
9:1 0
LÁSKOVÁ
9:30
PŘESTÁVKA NA KÁVU A ZÁKUSEK
9:50
10:20
Magda ZLÁMALOVÁ
(I. ročník PGS, školitel P.
Janda) kat I
ELEKTROCHEMICKÝ SENZOR S ELEKTRODOU
MODIFIKOVANOU POLYMERNÍ METHYLENOVOU
MODŘÍ PRO STANOVENÍ SULFANU
Martin RAJMON
(magisterské studium, FBMI
ČVUT, školitel Z. Bastl)
kat I
NOVÁ SKUPINA FUNKČNÍCH MOLEKULÁRNÍCH
STRUKTUR NA BÁZI CARBORAN THIOLŮ
11:00
Monika REMZOVÁ
Rathouský) kat I
MODIFIED SILICATE GELS FOR THE
CONSOLIDATION OF WEATHERED HISTORICAL
MATERIALS
11:20
Michal MAZUR
Čejka) kat I
INTERCALATION CHEMISTRY OF LAYERED
ZEOLITE PRECURSOR IPC-1P
10:40
Radka
METELKOVÁ
PŘESTÁVKA
11:40
11:50
12:10
Jan
SUCHÁNEK
12:30
Václav BLECHTA
(I. ročník PGS, školitel M.
Kalbáč) kat I
STUDY OF GRAPHENE’S PROPERTIES AND ITS
SENSOR APPLICATIONS
Marek PEDERZOLI
(I. ročník PGS, školitel
J. Pittner) kat I
TOWARDS ACCURATE AB INITIO SIMULATIONS
OF FLUORESCENT PROBES
Jan PŘECH
Čejka) kat I
SYNTHESIS AND PROPERTIES OF
GERMANOSILICATE AND TITANOSILICATE
FORMS OF CIT-5 ZEOLITE
--------
Ukončeny prezentace studentů kategorie I. (22 prací)
12:50
Monika KLUSÁČKOVÁ
(II. ročník PGS,
školitel P. Janda) kat II
ELECTROCATALYTIC OXIDATION OF
UNSATURATED HYDROCARBONS MEDIATED BY
PHTHALOCYANINE DERIVATE
PŘESTÁVKA NA OBĚD (PODÁVÁ SE V RESTAURACI OD 13:15)
13:10
14:45
Ana SANTIDRIÁN
(I. ročník PGS, školitel
M.Kalbáč) kat I
PURIFICATION AND CHARACTERIZATION OF
SINGLE WALL CARBON NANOTUBES
15:05
Marie OLŠINOVÁ
(II. ročník PGS, školitel M.
Cebecauer) kat II
EFFECT OF INTEGRAL PEPTIDES ON MODEL
MEMBRANES
Pavla SVRČKOVÁ
(II. ročník PGS, školitel M.
Fárník) kat II
CHLOROBENZENE - MASS SPECTRA,
PHOTODISSOCIATION DYNAMICS
Kateřina NOVÁKOVÁ
(II. ročník PGS, školitel
T. Navrátil) kat II
APPLICATION OF COPPER SOLID AMALGAM
ELECTRODE FOR DETERMINATION OF
DITHIOCARBAMATE FUNGICIDE
Zuzana
15:25
KOMÍNKOVÁ
15:45
16:05
16:45
Sabina PETRÁŠOVÁ
(II. ročník PGS, školitel H.
Balcar) kat II
POLYMER NETWORKS DERIVED FROM
ETHYNYLPYRIDINES
Radek ŽOUŽELKA
(II. ročník PGS, školitel J.
Rathouský) kat II
THE TOXICITY OF SILVER NANOPARTICLES TO
SCENEDESMUS QUADRICAUDA AND
CHLORELLA VULGARIS
17:25
Radka METELKOVÁ
J. Ludvík) kat II
SPECTRO-ELECTROCHEMICAL STUDY OF
CHROMIUM AMINOCARBENE REDUCTION
MECHANISM
17:45
Hana KVAPILOVÁ
(II. ročník PGS, školitel S.
Záliš) kat II
VARIATION OF PHOTOPHYSICAL PROPERTIES
N+
OF [REX(CO)3(DIIMINE)] COMPLEXES BY
MODIFICATION OF THE DIIMINE LIGAND: DFT
AND TRIR STUDY
17:05
Jakub
PASTVA
UKONČENÍ DRUHÉHO DNE KONFERENCE.
18:05
VEČEŘE V RESTAURACI OD 18:30 HODIN
18:05 18:30
Pro zájemce mimokonferenční
prezentace
Květa
STEJSKALOVÁ
PROGRAM
Čas
8:25
8:30
Předsedající
Představení vzdělávacích a popularizačních aktivit našeho
ústavu v projektu Tři nástroje v roce 2012/2013, něco málo
o novinkách - programy našich workshopů pro žáky ZŠ a j.
akce pro ostatní cílové skupiny…
3. dne konference
Přednášející
- pátek 26.4.2013
Název
Zahájení třetího dne semináře - pokračují prezentace studentů kategorie II.
Adéla FRIDRICHOVÁ
M. Horáček) kat II
YTTROCENE COMPLEXES CONTAINING
VARIOUSLY SUBSTITUTED CYCLOPENTADIENYL
LIGANDS: SYNTHESIS, CHARACTERIZATION AND
REACTIVITY
8:50
9:10
Petr
POSPÍŠIL
9:30
INTERACTION OF QUANTUM DOTS WITH
ORGANIC MOLECULES
Barbora LÁSKOVÁ
(III. ročník PGS, školitel
L.Kavan) kat II
PSEUDOCAPACITIVE CONTRIBUTION TO THE
TOTAL LITHIUM-ION STORAGE IN TIO2(B)
Jakub PASTVA (III. ročník
PGS, školitel J. Čejka) kat II
MESOPOROUS MOLECULAR SIEVES:
MATERIALS FOR HETEROGENEOUS
METATHESIS CATALYSTS AS WELL AS CO2
ADSORPTION
9:50
10:30
10:50
Jan SUCHÁNEK
(III. ročník PGS,
školitel Z. Zelinger) kat II
Hana
KVAPILOVÁ
11:10
Petr POSPÍŠIL
(III. ročník PGS, školitel M.
Hof) kat II
QUENCHING OF BADAN BY TRYPTOPHAN
CAUSED BY PHOTON INDUCED ELECTRON
TRANSFER IN MODEL MICELLAR SYSTÉM
Zuzana KOMÍNKOVÁ
M.Kalbáč) kat II
RAMAN SPECTROSCOPY STRONGLY DOPED
CVD-GRAPHENE
Tushar R. SHINDE
(III. ročník PGS, školitel H.
Balcar) kat II
RUTHENIUM CATALYSTS FOR METATHESIS AND
ETHENOLYSIS OF CARDANOL
PŘESTÁVKA
11:30
11:45
Jaroslav KOČIŠEK
M.Fárník) kat II
MOLECULAR BEAM EXPERIMENTS RELEVANT
FOR THE FORMATION OF POLAR
STRATOSPHERIC CLOUDS
Pavla CHLUBNÁ
(III. ročník PGS, školitel J.
Čejka) kat II
NEW ZEOLITES PREPARED BY POST-SYNTHESIS
METHODS
12:25
Milan BOUŠA
(III. ročník PGS, školitel L.
Kavan a O. Frank) kat II
RAMAN AND X-RAY PHOTOELECTRON
SPECTROSCOPIC CHARACTERIZATION OF
GRAPHENE OXIDE ELECTROCHEMICAL
REDUCTION
12:45
Ukončeny prezentace studentů kategorie II.
12:05
Pavla
SVRČKOVÁ
13:15 - SLAVNOSTNÍ VYHLÁŠENÍ VÝSLEDKŮ
SOUTĚŽNÍ KONFERENCE - V KONFERENČNÍM SÁLE
OBĚD V RESTAURACI od 13:30 hodin
Odjezd do Prahy - autobusem z parkoviště u zámku ve 14:45
(Návrat do Prahy k budově ÚFCH JH ca v 16:00 hodin.)
Seminář studentů ÚFCH JH, Konferenční centrum v Liblicích u Mělníka, 24. -26.4.2013
Seznam prezentujících studentů (40)
Kategorie I (22)
Kategorie II (18)
Diplomanti a studenti magisterského
studia a zájemci z řad bakalářů (12)
Studenti 2. ročníku PGS (9)
Bohuslav Jan (bakalářské studium, VŠCHT, stáž
u P.Jandy a H. Tarábkové)
Ederer Jakub (magisterské studium, PřF UK, stáž
u P.Jandy)
Hodík Tomáš (bakalářské studium, VŠCHT, stáž
u J. Pinkase)
Jurková Kateřina (bakalářské studium, PřF UK,
stáž u M.Kalbáče)
Košťál Pavel (magisterské studium, MFF UK,
stáž u M. Fárníka)
Lang Jakub (magisterské studium, PřF UK, stáž u
J.Pittnera)
Liška Alan (magisterské studium, PřF UK, stáž u
J. Ludvíka)
Rajmon Martin (magisterské studium, FBMI
ČVUT, stáž u Z.Bastla)
Rybárová Michaela (magisterské studium, FBMI
ČVUT, u stáž P.Španěla)
Svoboda Vít (bakalářské studium, VŠCHT, stáž u
O. Votavy)
Švaňa Matej (magisterské studium, PřF UK, stáž
u J.Pittnera)
Večeřa Miloš (bakalářské studiu., PřF UK, stáž u
M. Lamače)
Fridrichová Adéla (školitel M. Horáček)
Klusáčková Monika (školitel P. Janda)
Kvapilová Hana (školitel S. Záliš)
Metelková Radka (školitel J. Ludvík)
Nováková Kateřina (školitel T. Navrátil)
Olšinová Marie (školitel M. Cebecauer)
Petrášová Sabina (školitel H. Balcar)
Svrčková Pavla (školitel M. Fárník)
Žouželka Radek (školitel J. Rathouský)
Bouša Milan (školitel L. Kavan)
Chlubná Pavla (školitel J. Čejka)
Kočišek Jaroslav (školitel M. Fárník)
Komínková Zuzana (školitel M. Kalbáč)
Lásková Barbora (školitel L. Kavan)
Pastva Jakub (školitel J. Čejka)
Pospíšil Petr (školitel M. Hof
Shinde Tushar Raghunath (školitel
H. Balcar)
Suchánek Jan (školitel Z. Zelinger)
Blechta Václav (školitel M. Kalbáč)
Lachmanová Štěpánka (školitel M. Hromadová)
Mazur Michal (školitel J. Čejka)
Parisová Martina (školitel T. Navrátil)
Pederzoli Marek (školitel J. Pittner)
Přech Jan (školitel J. Čejka)
Remzová Monika (školitel J. Rathouský)
Santidrián Ana (školitel M. Kalbáč)
Višňák Jakub (školitel J. Pittner)
Zlámalová Magda (školitel P. Janda)
Hodnotící komise:
Roman Čurík
Otakar Frank
Petr Sazama
Romana Sokolová
.
Seminář studentů ÚFCH JH 2013 (studentská konference),
Konferenční centrum AV ČR v Liblicích u Mělníka, 24.-26.dubna 2013
STUDY OF GRAPHENE’S PROPERTIES
AND ITS SENSOR APPLICATIONS
Mgr. Václav Blechta
RNDr. Ing. Martin Kalbáč Ph. D.
Graphene is a monolayer of carbon atoms that can be viewed as an individual atomic
plane extracted from graphite [1]. Due to its unique structure, graphene exhibits
extraordinary physical properties, which have potential to employ graphene in many
applications [2]. This novel nanomaterial has been s tudied experimentaly and
theoretically by many authors since its discovery in 2004. In 2007 graphene-based field
effect transistor device was succesfully used for detection of individual gas molecule [3].
Our graphene is synthetized by chemical vapor deposition, then transfered onto
silicon/silicon-oxide substrate and after other treatment graphene is contacted by metal
electrodes. Raman spectroscopy, optical microscopy and at omic force microscopy are
used for characterization of synthetized graphene. Graphene solution-gated field effect
transistor (SG-FET) shows ambipolar transport characteristics, which is slightly modified
while graphene is doped; SG-FET with graphene channel is a promising candidate for
chemical sensor. In this presentation graphene's structure and basic properties are
briefly introduced, graphene solution-gated field effect transistor device is defined and
obtained results are shown.
References:
[1] Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang,Y.; Dubonos, S. V.;
Grigorieva, I. V.; Firsov,A.A. Science 2004, 306, 666-669.
[2] Huang, X.; Yin, Z. Y.; Wu, S. X.; Qi, X. Y.; He, Q. Y.; Zhang, Q. C.; Yan, Q. Y.; Boey,
F.; Zhang, H. Small 2011, 7, 1876-1902.
[3] Schedin, F.; Geim, A. K.; Morozov, S. V.; Hill, E. W. ; Blake, P.; Katsnelson, M. I.;
Novoselov, K. S. Natural Materials 2007, 6, 652-655.
NANOČÁSTICOVÁ ELEKTRODA:
ELEKTROCHEMICKÉ A NANOMORFOLOGICKÉ
VLASTNOSTI Ni/HOPG ELEKTRODY PŘIPRAVENÉ
RŮZNÝMI METODAMI DEPONOVÁNÍ
Jan Bohuslav
Ing. Pavel Janda, CSc.
RNDr. Hana Tarábková, PhD.
Elektroda byla připravena depozicí nanočástic niklu, resp. oxidu a hydroxidu niklu na
bazální rovinu vysoce orientovaného pyrolytického grafitu (HOPG) sloužícího jako
kolektor. K deponování bylo využito technik: UHV-napařování, spin-coatingu a
sprejování vodné suspenze Ni(OH)2. Práce porovnává různými technikami deponovaný
Ni(OH)2 z hlediska nanomorfologie a její změny (AFM) a reakce přenosu náboje
(voltametrie). Napařováním a ablací ve vakuu nebo v inertním plynu (Ar) lze získat
niklové nanočástice, které se teprve na povrchu HOPG oxidují na oxid resp.
oxohydroxid Ni(II), nanášením suspenze Ni(OH)2 spin-coatingem a s prejem jsou na
povrchu imobilizovány přímo nano-lamely Ni(OH)2. Proces lze finalizovat kalcinací.
Niklové nanočástice deponované na inertním vodivém substrátu slouží jako model
nanočásticové elektrody s možným uplatněním ve zdrojích proudu.
RAMAN AND X-RAY
PHOTOELECTRON SPECTROSCOPIC
CHARACTERIZATION OF GRAPHENE
OXIDE ELECTROCHEMICAL
REDUCTION
Mgr. Milan Bouša
Mgr. Otakar Frank, Ph. D.
Prof. RNDr. Ladislav KAVAN, DSc.
Previously we reported on an effect of a spontaneous electrochemical activation during
the electrochemical cycling of a few-layered graphene oxide (FLGO) performing as a
conductive additive to a nanocrystalline LiFePO4 olivine. Based on electrochemical, IR
and Raman studies we suggested that a gradual in-situ reduction of FLGO is
responsible for this activation.
We studied the reduction of FLGO and graphene nanoplatelets during electrochemical
cycling. Using in-situ Raman spectroelectrochemistry we found out the redox processes
are reversible for graphene nanoplatelets and irreversible for graphene oxide. Hence,
the primary degree of oxidation has an influence on the initial reduction process. Our Xray photoelectron spectroscopy measurements show a preferential removal of carboxy
and hydroxy functional groups initially present in FLGO structure, while most of the
epoxy groups remain present in the material. Furthermore, the behavior of a pristine
FLGO electrode was studied during redox processes and measured throughout
alternating long-time reduction, oxidation and at open circuit potential (relaxation). The
acquired data show a certain degree of reversibility even in the redox behavior of FLGO,
which is, however, switched to a c ompletely different pattern after crossing a di stinct
reduction degree.
Acknowledgements. This work was supported by FP7-Energy-2010-FET project Molesol
(Contract No. 256617).
MULTIKOMPONENTNÍ ANALÝZA
VZORKU POUŽITÍM
VÍCEELEKTRODOVÉHO SYSTÉMU
Bc. Jakub Ederer
RNDr. Karel Nesměrák, Ph.D.
Při analýze vzorku, který obsahuje více analytů je selektivita jedné elektrody v rámci
směsi mnohdy nedostatečná. Proto je výhodnější využití systému tvořeného větším
počtem elektrod, které poskytují více informací o analyzovaném vzorku. Selektivita
takovéhoto systému je vzájemně posunuta a je vyšší než selektivita při použití
jednotlivých elektrod individuálně. V tomto systému bude použita metoda cyklické
voltametrie v tříelektrodovém uspořádání na pevných elektrodách z různých
materiálů (Au, Pt, HOPG, Pt, amalgámové elektrody). Získaná a par ametricky
zpracovaná data budou použita pro vytvoření tzv. „finger-printu“ analytu.
Pro tento účel byly zvoleny dvě organické kyseliny, s cyklem ve své molekule.
Kávová kyselina, u níž byly prokázány antioxidační, antimutagenní a
antikarcinogenní účinky [2]. Askorbová kyselina, která je běžně používané
konzervační činidlo používané během výroby a skladování vín, jejímž vlivem dochází
k oxidativnímu hnědnutí bílých vín [1]. Zvolené kyseliny byly prozatím analyzovány
v modelovém roztoku.
References:
[1] Lopes, P.; Drinkine, J.; Saucier, C.; Glories, Y. Anal. Chim. Acta. 2006, 555,
242–245.
[2] Fracessetti, D.; Lawrence, N.; Tredoux, A. G. J.; Tirelli, A.; Nieuwoudt, H. H.; Du
Toit, W. J. Food Chemistry, 2011, 128, 1136–1142.
YTTROCENE COMPLEXES
CONTAINING VARIOUSLY
SUBSTITUTED CYCLOPENTADIENYL
LIGANDS: SYNTHESIS,
CHARACTERIZATION AND
REACTIVITY
Ing. Adéla Fridrichová
Mgr. Michal Horáček Ph.D.
The interest in the chemistry of group 3 m etals and or ganolanthanide compounds
has increased recently because these complexes exhibit an enor mous potential in
homogeneous catalysis. Alkyl and hydride species, Cp*2LnR (Cp* = η5-C5Me5; Ln =
Sc, Y, La, Ce, Nd, Sm, Lu; R = CH(SiMe3)2, Me, H) have been shown to be active in
selective C-C bond formation and C-H/C-X bond activation. Typical examples are
found in transformations of olefins (oligo/polymerization, hydrogenation,
hydroboration, hydrosilylation, amino-olefin hydroamination/cyclization) and alkynes
(oligomerization, hydrogenation, and hydroamination/cyclization) [1,2].
The aim of the presented work was the synthesis and characterization of a set
of new mixed yttrocene complexes of the type (C5Me4SiMe3)Y(L)(µ-Cl)2M(THF)2 (L =
C5H5, C5Me5, C5Me4SiMe2H, C5Me4CH2Ph; M = Li, K) prepared by stepwise
treatment of the tetrahydrofurane adduct YCl3·3.5THF with one equivalent of
Li(C5Me4SiMe3) and c orresponding lithium or potassium salt of the second Cp-ring
(L). Subsequently, methylation reactions of these complexes using MeLi was
investigated.
Fig. Methylation of yttrocene complex (C5Me4SiMe3)Y(C5Me4CH2Ph)(µ-Cl)2K(THF)2.
References:
[1] Molander, G. A. and Romero, J. A. C. Chem. Rev. 2002, 102, 2161-2185.
[2] Gromada, J.; Carpentier, J. F.; Mortreux, A. Coord. Chem. Rev. 2004, 248, 397410.
SWEET TITANOCENES AND
FERROCENES
Tomáš Hodík
Mgr. Jiří Pinkas, Ph. D.
The discovery of cytotoxic activity of cis-diamminedichloroplatinum(II) in 1965
initiated investigation of cytotoxic properties of other transition metal (Ti, Fe, Ru, Zr
etc). Similar motif of cisplatin with titanocene dichloride caused the interest about it
early 80´s. It was the first non-platin potential cytostatic which entered clinical trials,
however it is relatively low anticancer activity and nephr otoxicity precludes further
testing. During last decade was discovered that substitution at cyclopentadienyl ring
caused higher anticancer activity, less toxicity etc.
The aim of our work has been synthesis of organometallic compounds derived from
titanium and iron which are substituted by D-xylose, D-ribose etc. at cyclopentadienyl
ring. We assume that presence of a carbohydrates moiety at a metallocene periphery
may reduce toxicity, improve solubility and allow selective transport into cancer cell.
In my contribution synthesis and characterization of prepared substituted titanocene
and ferrocene compounds will be di scussed. Cytotoxic activity of selected
compounds will be presented too.
HT 38 24h
0.8
O
OH
O
O
O
Fe
HO
O
O
IC50= 32,41 uM
0.6
0.4
0.2
0.0
10 - 8
10 - 6
10 - 4
10 - 2
10 0
10 2
10 4
Fig. 1: Structure of ferrocene bearing D-xylose and graph showing dependence its activity
on concentration (IC50 = concentration of the active substance which lead to
reduction of amount of cancer cell to half)
Reference:
1. Rosenberg, B.; Vancamp, L.; Krigas, T. Nature 1965, 205 (698).
2. Köpf, H.; Köpf-Maier, P. Chem. Rev. 1987, 87, 1137–1152.
NEW ZEOLITES PREPARED BY
POST-SYNTHESIS METHODS
Mgr. Pavla Chlubná
Prof. Ing. Jiří Čejka, DrSc.
Zeolites are traditionally 3D-framework microporous crystalline aluminosilicates with a
wide range of applications1. Recently, the group of zeolites has been expanded by the
development of 2D zeolites prepared through the “bottom-up” (direct) synthesis as so
called zeolite precursors, e.g. MCM-22P2. These 2D mono-layer materials can be postsynthetically modified into materials with improved textural properties.
It was lately discovered that germanosilicate UTL undergoes structural changes in acid
environment where D4R units are removed and only UTL layers remain3. This “topdown” synthesis produces a new lamellar material IPC-1P and offers a new attitude in
the synthesis of zeolitic materials. It is possible to expand the interlayer space by
treatments like swelling and pillaring, similarly like in the case of MCM-22P4, or we can
organize the layers and reconnect them again. Choosing and controlling of the linkers
used for reassembling give us the tool for preparation of materials with predictable
structures, like zeolites IPC-2 and IPC-4 (IZA code PCR). They preserve the UTL-like
layers but differ in new linkers between them and also in pore sizes (Fig. 1).
UTL
IPC-2
IPC-4 (PCR)
Fig. 1 The structures of UTL, IPC-2 and IPC-4. The layer topology (in red) is common to all three materials
which differ in sized linkers (in blue).
The novel strategy called ADOR (assembly-disassembly-organization-reassembly)
offers new possibilities in the synthesis of zeolitic materials. There are some application
limitations like chemical composition of the parent zeolite or presence of D4R units,
however, it has been already applied on other germanosilicates (IWW, IWR) with first
promising results.
We would like to acknowledge Grant Agency of the Czech Republic (P106/12/G015) for the financial
support.
References:
1 Čejka, J.; van Bekkum, H.; Corma, A.; Schüth, F. (Ed.) Introduction to zeolite science and practise,
Stud. Surf. Sci. Catal. 2007, Vol. 168, 3rd Ed., Elsevier, Amsterdam.
2 Roth, W. J.; Čejka, J. Catal. Sci. Technol. 2011, 1, 43-53.
3 Roth, W. J.; Shvets, O. V.; Shamzhy, M.; Chlubná, P.; Kubů, M.; Nachtigall, P.; Čejka, J. J. Am. Chem.
Soc. 2011, 133, 6130-6133.
SINGLE-LAYER MOS2 AND ITS
NTERACTION WITH GRAPHENE
Kateřina Jurková
RNDr. Ing. Martin Kalbáč., Ph. D.
Various two dimensional nano-materials have recently attracted plenty of interest due
to their physical and electrical properties. Since its discovery in 2004, a lot of attention
has been focussed on graphene, one atom thick layer of carbon atoms packed with
hexagonal lattice. Apart graphene, also its analogues such as MoS2 have got into the
centre of interest. [1]
Single layer MoS2 was initially prepared by mechanical exfoliation which is still the
most effective method for its preparation. Though other various methods have been
developed, optical microscopy, Raman spectroscopy and a tomic force microscopy
(AFM) are the most effective methods for identification the thickness of both graphene
and MoS2 layers. [2] [3]
Proper understanding to electrical properties of these materials is essential for their
potential future application in nano-electronics. [4] One of the things in which we are
interested in our laboratory is the investigation of spectroelectrochemical properties of
these materials.
The content of my lecture will be a brief characterization of single layer (SL) MoS2 by
AFM and Raman spectroscopy and its interaction with CVD graphene.
References:
[1] Yin, Zongyou; Li, Hai AcsNano 2012, 6, No. 1, 74–80.
[2] Zhou, Hai-qing; Yu, Fang Chemical Physics Letters 2011, 518, 76–80.
[3] Li, Hai; Lu, Gang small, 2012 8, No. 5, 682–686.
[4] Kalbac, M; Reina-Cecco, A. AcsNano 2010, 4, No. 10, 6055–6063.
ELECTROCATALYTIC OXIDATION OF
UNSATURATED HYDROCARBONS
MEDIATED BY PHTHALOCYANINE
DERIVATE
Mgr. Monika Klusáčková
Unsaturated hydrocarbons as ethylene and propylene are not only gases of
considerable industrial significance but also typical air pollutants that are produced in
global quantities. These gases have high photochemical reactivity and m ay form
photochemical smog with possible impact on a global scale. Therefore the monitoring of
hydrocarbons is critical for quality of environment [1, 2].
The oxidation of ethylene and propylene was studied on basal plane of highly ordered
pyrolytic graphite (HOPG) electrode with deposited thin layer Co-phthalocyanine
derivate as a m ediator and in aqueous buffer phosphate solution as an e lectrolyte.
Cyclic voltammetry, backscattering VIS spectroscopy and atomic force microscopy were
utilized. The choice of tetrapyridinoporphyrazines as a mediator was given by its redox
properties, ability to form low soluble, electrically conducting film on the electrode
surface [3, 4]. Our interest has been focused on conditions for electrocatalytic oxidation
of these molecules on modified electrode.
Acknowledgements
This work was financially supported by the Research project MSM0021620857 of the
Ministry of Education, Youth, and Sports of the Czech Republic, by grant project
SVV267215 of Charles University of Prague, by Grant Agency of the Academy of
Sciences of the Czech Republic (Contract IAA 400400804) and by the EC 7th FP project
ORION (Contract No. NMP-229036).
Reference:
[1]
Wama, R., Plashnitsa, V. V., Elumalai, P., Utiyama, M., Miura, N.: Solid State
Ionics. 2010, 181, 359-363.
[2]
Graewe, B., Rang, A., Schalley, Ch. A., Haubrich, J., Bargon, J.: Sensor Actuator,
2006, 119, 302-307.
[3]
Tse, Y. H., Janda, P., Lever, A. B. P.: Anal. Chem. 66 1994, 66, 384–390.
Chen, J., Zhang, J., Tse, Yu-H., Janda, P., Dharamdat, Ch., Lever, A. B. P.:
[4]
J Porphyr Phthalocya. 2006, 10, 1238-1248.
MOLECULAR BEAM EXPERIMENTS
RELEVANT FOR THE FORMATION OF
POLAR STRATOSPHERIC CLOUDS
Mgr. Jaroslav Kočišek
Mgr. Michal Fárník, DSc.
Results of two independent experimental studies [1, 2] are presented, which could
illuminate the processes leading to the formation of ice particles in the Polar
Stratospheric Clouds (PSCs). PSCs serve as an important catalysts of the ozone
depletion cycle. Two types of PSC particles are present in the Stratosphere: HNO3/H2O
ices in the type Ia PSCs and pure water ices in the type II PSCs. In the molecular beam
experiments, these particles could be mimicked by large mixed HNO3/H2O clusters and
pure H2O clusters, respectively.
At first we explore the formation of the type Ia PSCs. Experiments combining the Na
pickup technique followed by the UV photoionization and the precise electron ionization
mass spectroscopy demonstrate the importance of nitric acid in the clustering process
[1]. We show that the mixed HNO3/H2O clusters in the supersonic expansions are
exclusively formed by the water freezing on the HNO3 condensation core. In the
atmosphere, condensation is explained to process by the nucleation of H2O on t he
sulphuric acid core. Our observation shows that nucleation on the HNO3 core can be
effective at low temperature and the direct channel can significantly contribute to the
PSCIa particle formation.
In the second experiment we focus on the adsorption of additional molecules on the
large water clusters. The experiment combining the pickup technique with the precise
velocity measurement [2] shows that the water clusters interact with adsorbing
molecules via dipole interactions. The observation leads to significantly higher values of
adsorption cross sections in the comparison to the generally used geometrical ones.
Both studies show that the formation of PSCs is significantly faster than expected,
what can have impact on the future ozone level predictions.
[1] Lengyel, J.; Pysanenko, A.; Kočišek, J.; Poterya, V.; Pradzynski, C. C.; Zeuch, T.; Slavicek, P.; Farnik,
M. Journal of Physical Chemistry Letters, 2012, Vol.3, p. 3096-3101, ISSN-1948-7185
[2] Lengyel J., Kočišek J., Poterya V., Pysanenko A., Svrčková P., Fárník M., Zaouris D.K., Fedor J.,
Journal of Chemical Physics 137(3), 2012, 034304.
RAMAN SPECTROSCOPY STRONGLY
DOPED CVD-GRAPHENE
Mgr. Zuzana Komínková
RNDr. Ing. Martin Kalbáč, Ph.D.
Raman spectroscopy is s ensitive characterization method for carbon-based materials
such as graphene, carbon nanotubes or peapods due to the strong resonant
enhancement of the Raman signal.
The Raman spectra from sp2 nano-carbons are composed of first-order and higher-order
Raman modes, as well as disorder-induced features. The important Raman active
bands, which appear in Raman spectra of all graphene-based materials, are the
tangential displacement mode (TG, G) and the high frequency, two phonon mode (G´,
2D). In some graphene sample, the D band is also found and is believed to indicate the
presence of defects as in ordinary graphite.
Well-established method to study the electronic structure of carbon nanostructures is
in-situ Raman spectroelectrochemistry. Electrochemistry allows precise and
well-controlled doping of carbon materials. The change in electrochemical potential
leads to a shift of the Fermi level which is reflected in a change of Raman spectra.
Raman spectroscopy and in-situ Raman spectroelectrochemistry have been applied to
study chemical vapor-deposition-grown graphene coated with layers of polyelectrolytes.
In our study we focused on analyzing the change of the Raman shift and the Raman
intensity of the G and G´ bands as a function of the electrode potential. Due to
polyelectrolyte coating a strong doping level could be achieved. The intensity of the G´
band decreases with increasing magnitude of the electrode potential, but the G band
exhibits a more complex behavior. An anomalous increase in the intensity of the G band
at both high positive and negative potentials has been observed.
References:
Kalbac, M., ACS Nano, 2010, 4(10), 6055-6063.
Kalbac. M., Nano Lett., 2011, 11(5), 1957-1963.
STUDIUM DYNAMIKY FOTODISOCIACE
ZOBRAZOVACÍ METODOU IMAGING
Pavel Košťál
Mgr. Michal Fárník Ph.D.
Při studiu dynamiky elementárních chemických reakcí je klíčové současně měřit
rozdělení rychlostí produktů chemických reakcí a zároveň jejich úhlové rozdělení. Určení
vnitřní energie a rychlostí všech produktů reakce je použito ke studiu molekulárních
reakcí, procesů přenosu energie a fotodisociace [1]. K tomuto účelu se využívá iontové
zobrazování, díky kterému určíme trojrozměrné rozdělení rychlostí vybraného stavu
zvoleného produktu reakce. Navíc, když se omezíme pouze na fotodisociaci, při které se
uvolní právě dva fragmenty, lze ze zákona zachování energie a hybnosti určit vnitřní
stav druhého produktu.
Iontové zobrazování [2] je experimentální medota pro měření směru a velikostí rychlostí
vzniklých produktů po fotodisociaci [3] či po chemické reakci. Tato technika používá
dvoudimenzionální, pozičně senzitivní detektor k záznamu pozice příletu vzniklého
produktu.
V přednášce bude představena fotodisociace systémů obsahující chlor jako například
CH3Cl, freony apod., které jsou atmosféricky relevantní systém, protože se podílejí
na tvorbě ozónové díry.
Poděkování:
Tento projekt byl podporován z grantu GAČR 203/09/0422.
References:
[1] Houston, Paul L. (1987), "Vector correlations in photodissociation dynamics", J. Phys.
Chem., 91 (21): 5388–5397, doi: 10.1021/j100305a003
[2] http://en.wikipedia.org/wiki/Photofragment-ion_imaging
[3] Whitaker, Benjamin J (ed.) (2003), Imaging in Molecular Dynamics, Cambridge
University Press, ISBN 0 521 81059
VARIATION OF PHOTOPHYSICAL
PROPERTIES OF [ReX(CO)3(DIIMINE)]N+
COMPLEXES BY MODIFICATION OF THE
DIIMINE LIGAND: DFT AND TRIR STUDY
Ing. Hana Kvapilová
Ing. Stanislav Záliš, CSc.
Photophysical behavior of Re(I) tricarbonyl diimine complexes [ReX(CO)3(diimine)]n+
strongly depends on the coordination sphere. Character of the lowest lying excited
states and their relative energies, properties and r eactivity can be c ontrolled by
variations of the ligand structure and/or the medium. In this talk complexes with a halide
atom in place of the ligand X and with various types of diimine ligands will be described.
Excited states participating in the ultra-fast intersystem crossings (~ps time scale) of
these molecules were studied using femtosecond infrared spectroscopy experiments, so
called time-resolved IR spectroscopy (TRIR). In this method, shifts of CO stretching
frequencies point to the character of excited states and the time development of the
spectra indicates kinetic behavior.
In order to understand the character and dynamics of optically excited states, DFT
calculations were performed on these systems. The theoretical model employed hybrid
functionals with triple-ζ polarized basis sets and PCM solvent correction. Optimized
excited-state geometry was calculated for the lowest singlet and t riplet states by the
unrestricted Kohn-Sham (UKS) or time dependent DFT (TDDFT) approach. Calculations
of vibrational frequencies were performed on harmonic level and also with anharmonic
correction using generalized second-order vibrational perturbation (GVPT2) model. The
calculated shifts of CO stretching frequencies well reproduce experimentally measured
TRIR spectra and help to describe the excited-state behavior of these compounds.
References:
Vlček, A. Jr.; Záliš, S. Coord. Chem. Rev. 2007, 251, 258-287.
Baková, R.; Chergui, M.; Daniel, C.; Vlček, A. Jr.; Záliš, S. Coord. Chem. Rev. 2011,
255, 975-989.
REDUCTION OF SELECTED BRANCHED
EXPANDED PYRIDINIUM CATIONS
Mgr. Štěpánka Lachmanová
Mgr. Magdaléna Hromadová, Ph.D.
The Branched expanded pyridinium molecules are among the most extensively studied
compounds because of their redox properties. Their characteristics depend strongly on
the structure of the molecule. [1, 2]
In this work we have studied the redox properties of four expanded pyridinium cations
(their structures are shown in Fig. 1) by various electrochemical methods with the
emphasis put on the redox processes of the electron transfer. Although the structures of
the studied molecules seem to be quite similar, the process of their reduction is
completelly different. The compounds 1-N-methyl-2,4,6-triphenylpyridinium (A) and
1',3',5'trimethyl2,4,6triphenyl1,4'-bipyridine-1,1'-diium (B) were reduced i n two
separate one-electron transfer steps. 1'methyl2,4,6triphenyl1,4'bipyridine1,1'diium
(C) and 1',3,5trimethyl2,4,6triphenyl-1,4'-bipyridine-1,1'-diium (D) accept two electrons
too, but in a single two-electron transfer. This contribution describes the determination of
the heterogeneous rate constants for the compounds A to D.
Fig. 1: Studied molecules
References:
[1] Fortage J., Peltier C., Perruchot C., Takemoto Y., Teki Y., Bedioui F., Marvaud V., Dupeyre
G., Pospisil L., Adamo C., Hromadova M., Ciofini I., Laine P.: J. Am. Chem. Soc. 2012, 134,
2691-2705
[2] Fortage J., Peltier C., Nastasi F., Puntoriero F., Tuyeras F., Griveau S., Bedioui F., Adamo
C., Ciofini I., Campagna S., Laine P.: J. Am. Chem. Soc. 2010, 132, 1670016713
Acknowledgement:
This work was supported by the Academy of Sciences of the Czech Republic (M200401202).
AN AB INITIO INVESTIGATION OF THE
ISOMERIZATION OF BICYCLOBUTANE:
DESCRIPTION OF THE CONROTATORY
AND DISROTATORY STATES
Bc. Jakub Lang
Mgr. Jiří Pittner Dr. rer. nat.
Standard quantum chemical methods are able to calculate the activation barrier of the
isomerization of bicyclo[1.1.0]butane to Buta-1,3-diene in excellent agreement with the
experimental values. However, t he single-reference methods fail in s ituations where
static correlation is important. One of such situations is a t ransition state of the
disrotatory pathway channel, which exhibits a strong biradical character. To account for
a static correlation it is necessary to apply multireference methods such as
Multiconfiguration self consistent field (MCSCF), multireference configuration interaction,
and multireference Coupled Clusters (CC) methods.
In my lecture, the results of calculations performed with multireference wave function
methods, in particular using the multireference CC methods developed in our group, will
be presented.
References:
Kinal, A.;Piecuch, P.; J. Phys. Chem. A 2007, 111, 734-742.
Lutz, JJ.; J. Phys. Chem. 2008, 995, 62-71.……
PSEUDOCAPACITIVE CONTRIBUTION TO
THE TOTAL LITHIUM-ION STORAGE IN
TiO2(B)
Mgr. Lásková Barbora
Prof. RNDr. Ladislav Kavan, DSc.
RNDr. Markéta Zukalová, Ph. D.
TiO2 belongs to widely studied semiconducting metal oxides. Tetragonal modification of
titanium dioxide (anatase) and monoclinic one ( TiO2(B)) are both attractive for
applications in Li-ion batteries, however, TiO2(B) shows more facile Li+ insertion in
comparison with that in anatase. The total stored charge in these materials can be
separated into charge associated with capacitive processes and charge corresponding
to diffusion-controlled insertion processes. The analysis of cyclic voltammograms of
TiO2(B) and anatase using the previously published method1 can give us more detailed
information about different charging machanisms of these materials and explains the
facilitated Li+ insertion in TiO2(B). The pseudocapacitive contribution to the total stored
charge was determined for both types of materials. The difference of 30% was found
between capacitive contributions in TiO2(B) and in reference anatase materials (C240,
P90). Deconvolution of cyclic voltammograms also indicates different capacitive
contributions of the two particular voltammetric peaks of TiO2(B).
References:
[1] Wang, J.; Polleux, J.; Lim,J.; Dunn, B.; J. Phys. Chem. C 2007, 111, 14925
Acknowledgement:
This work was supported by the Grant Agency of the Czech Republic (contract No. 1307724S and P108/12/0814).
ELECTROCHEMICAL REDUCTION
OF STRUCTURALLY MODIFIED
POLYNITROCALIX[4]ARENES
Bc. Alan Liška
Prof. RNDr. Jiří Ludvík, CSc.
Calixarene skeleton is a s table supramolecular frame which is electrochemically
inactive. Suitable substitution on the upper and lower rim, eventually structure
modification or introduction of heteroatoms lead to unusual and surprising properties of
this system.
The nitro substituents on the upper rim make the molecule reducible. Presence of one,
two, three or four nitro groups in the same molecule provokes principal questions: What
is the intramolecular electronic interaction between them? Are they reduced
simultaneously or stepwisely? What are the respective intermediates in aprotic media?
The electrochemical study revealed that reduction of the tetranitrocalix[4]arenes starts
with two 2-electron reversible waves corresponding to the presence of two different
couples of equivalent nitro groups. This result reflects well the finding of the X-ray
structural analysis, that the "calix" in fact, is not circular, but pinched with a strong "πstacking" of the opposite benzene rings. The full reversibility points to the fact that the
four-electron intermediate involves four equivalent non-communicating nitro radical
anions. This stable tetraanion tetraradical is then able to be reduced by a following
broad 12-electron wave, yielding the tetrahydroxylamino derivative. Product of total
reduction - the tetraamino derivative - can be us ed for introduction of other functional
groups and prolongation of the pendant chains.
The partial or full reduction of these molecules opens the possibility of an el ectrontransfer induced change in geometry of the parent calixarene, moreover, the reduced
nitrogroups can serve as ligands enabling complex formation or host-guest interaction.
Both UV-Vis-NIR spectroelectrochemical measurements (IFW Dresden) of pure
compounds and complexation experiments with alkali metal cations were performed and
the results discussed.
The recently synthesized new derivatives with nitro groups in meta-positions and with
bridging sulfur atoms are promissing as surface active species being able to modify the
electrode.
The experimental findings were correlated with quantum chemical calculations and
discussed.
INTERCALATION CHEMISTRY OF
LAYERED ZEOLITE PRECURSOR IPC-1P
Mgr. Michal Mazur
The discovery of two-dimensional layered zeolites opened many opportunities to design
new structures and zeolite architectures[1],[2]. One of the recent breakthroughs in this
area has been the conversion of the UTL zeolite into a l amellar precursor (IPC-1P)[3].
The change is attributed to the degradation of Ge-containing double four rings (D4R)
connecting the ‘UTL’/IPC-1P layers.
Post-synthesis modification of IPC-1P afforded variety of structures like swollen, pillared
and stabilized. Remarkably, it also produced previously unknown zeolites IPC-2 and
PCR (IPC-4). These zeolites were synthesized via newly proposed synthetic mechanism
ADOR (A – assembly, D – disassembly, O – organization, R – reassembly). The ADOR
approach is believed to be a general strategy that will lead to the preparation of new
zeolites.
We investigated the intercalation chemistry of IPC-1P with various organic compounds.
We look for possibility of obtaining additional, more expanded materials with preserved
‘UTL’ layers.
X-ray powder patterns proved that various organic agents can expand IPC-1P layers
with different distances between them. Calcination of the intercalated IPC-1P leads to
materials similar to IPC-4 or IPC-2 zeolites but also some solids with unknown structure.
Selected materials were pillared with tetraethyl orthosilicate to fix the separation of
layers permanently. Obtained materials were characterized using XRD, SEM and
adsorption of nitrogen. Post-intercalation pillaring showed promise in producing new,
larger pore materials.
References:
1.
Čejka J., Stud. Surf. Sci. Catal., 2005, 157, 111-134.
2.
Roth W. J.; Čejka J., Catal. Sci. Technol., 2011, 1, 43-53.
3.
Roth W. J.; Shvets O. V.; Shamzy M.; Chlubná P.; Kubů M.; Nachtigall P.; Čejka J., J.
Am. Chem. Soc., 2011, 133, 6130-6133.
SPECTRO-ELECTROCHEMICAL STUDY
OF CHROMIUM AMINOCARBENE
REDUCTION MECHANISM
Ing. Radka Metelková
Prof. RNDr. Jiří Ludvík, CSc.
Fischer type aminocarbene complexes are widely used in various organic syntheses but
they are also a pr omising material in redox catalysis. Nevertheless, for such use the
redox mechanism needs to be inevstigated.
Our previous studies dealt with influence of various substitutions in aminocarbene
complexes on t heir redox behaviour [1]. Recently, a det ail study of their reduction
mechanism is carried on by means of electrochemical and spectroelectrochemical
methods.
Reduction mechanism was investigated on a s eries of chromium aminocarbene
complexes substituted by a heterocycle: [(CO)5Cr=C(NMe2)het, where het= 2-(resp.3)furyl, 2-(resp.3-)thienyl), 2-N(CH3)pyrrole]. Cyclic voltammetry(CV) on various electrode
materials was used for distinguishing the mechanism but further research was needed,
so we did bulk electrolysis together with reduction products identification by mass
spectroscopy (MS).
Reduction (CV) of the whole series proceeds in a similar way: irreversible electrode
reduction is followed by a c hemical reaction. The spectroelectrochemical study has
shown that follow-up reaction is dimerization of carbene carbon part of the original
molecule. The resulting dimer is able to form three isomers so the real product of the
reaction needs to be distinguished. NMR spectroscopy was thus used as a confirmation
of MS results and identification of the product isomer.
References:
[1] Metelková R, Kvapilová H, Hoskovcová I, Tobrman T, Ludvík J; Electrochim. Acta
2012, 82, 470-477
VYSOKOTLAKÁ SYNTÉZA FLUORESCENTNÍCH
A KATALYTICKY AKTIVNÍCH SULFIDŮ
Roman Nebel
Ing. Petr Krtil CSc.
Syntéza nekonvenčních materiálů s definovanými vlastnostmi je jedním z určujících
trendů současného materiálového výzkumu. Praktický vývoj nových materiálů využívá
dvou základních strategií, „racionálního designu“ nebo kombinatorického postupu. První
strategie je založena na detailním pochopení fyzikálně chemické podstaty funkčnosti
materiálu, která umožňuje teoretický předvýběr perspektivních struktur a jejich cílenou
syntézu, druhá možná strategie využívá systematického průzkumu existujících fází
a jejich následné charakterizace.
Tento přístup je aplikovatelný na jakýkoliv typ materiálů a jeho praktická využitelnost je
omezena pouze dostupností jednotlivých fází. Potenciál kombinatorického přístupu lze
výrazně zvýšit, pokud je experimentu přístupna oblast metastabilních fází. Syntéza
za vysokých teplot a tlaků (750 – 1000°C, 0,6 – 5 GPa) představuje preparativní postup,
spadající do t éto strategie, vhodný k cílené modifikaci elektronové struktury pevných
látek.
Příspěvek bude zaměřen na demonstraci tohoto syntetického postupu na případě
ternárních a kvartérních sulfidů v systémech Ca-Zn-S, Sr-Zn-S, Ca-Ba-Zn-S, Sr-Si-S,
Sr-Zn-Si-S. Podrobně bude diskutována zejména aplikace difrakčních
a mikroskopických technik při identifikaci reakčních produktů.
APPLICATION OF COPPER SOLID
AMALGAM ELECTRODE FOR
DETERMINATION OF
DITHIOCARBAMATE FUNGICIDE
Ing. Kateřina Nováková
Assoc. Prof. Dr. Ing. Tomáš Navrátil
Thiram belongs to the widely used protective dimethyldithiocarbamate fungicides. This
compound is used for control of many fungal diseases in cropping fruits, vegetables and
ornamentals. Thiram is hazardous to the environment. The main problem of this
dithiocarbamate pesticide in soils is based on its persistence 1,2. Thiram is irritating to
the eyes, skin, and respiratory tract. Thiram creates complexes with copper. These
interactions can have the effect on its toxicity 3,4.
The voltammetric behavior of thiram was studied by differential pulse voltammetry (DPV)
and cyclic voltammetry (CV) at polished (p-CuSAE) and mercury meniscus-modified
(m-CuSAE) copper solid amalgam electrode with inner diameter 1.5 mm. The optimum
conditions for DPV determination of this fungicide were received in Britton-Robinson
buffer. The reaction mechanism was studied using CV and elimination voltammetry with
linear scan (EVLS). DPV with optimized parameters was used for determination of
thiram in analyzed solutions. The limits of detection were calculated as 16 nmol L-1
(tacc = 100 s) for m-CuSAE and 23 n mol L-1 (tacc = 60 s ) for p-CuSAE. The proposed
method was tested in real sample solutions.
References:
(1)
Sharma, V. K.; Aulakh, J. S.; Malik, A. K. J. Environ. Monit. 2003, 5, 717.
(2)
Malik, A. K.; Kaul, K. N.; Lark, B. S.; Rao, A. L. J. Pestic. Sci. 1998, 53, 104.
(3)
Nováková, K.; Navrátil, T.; Dytrtová, J.; Chýlková, J. J. Solid State Electrochem.
2013, 1.
(4)
Zhao, Y.-G., Zheng, X.-W., Huang, Z.-Y., Yang, M.-M. Anal. Chim. Acta 2003,
482, 29.
Acknowledgments
The research was supported by GACR (project No. P206/11/1638 and project No.
P208/12/1645) and by the Students’ Grant of University of Pardubice (No. SGFChT05/2012).
EFFECT OF INTEGRAL PEPTIDES ON
MODEL MEMBRANES
Mgr. Marie Olšinová
Mgr. Marek Cebecauer, Ph.D.
Biological membranes are essential parts of the cell that separate outer and inner space
in or around the cell. Membranes consist of a mixture of lipids and integral and
peripheral proteins. Protein localisation and function is influenced by the surrounding
lipid and protein environment. Transmembrane domains (TMD) of proteins mediate the
closest contact with lipids. In this study, we tested how mutual interactions of lipids and
proteins influence membrane organisation. Proteins are represented by synthetic
peptide derived from the TMD and proximal amino-acid residues of LAT protein, and by
WALP. WALP is an artificial peptide frequently used in biophysical studies1 as typical
TMD of plasma membrane protein. Model membranes (giant unilamellar vesicles;
GUVs) were prepared using low melting temperature lipid DOPC, cholesterol and
peptide. Changes in diffusion of fluorescently-labelled lipid in the absence or presence of
TMD peptides and cholesterol were monitored by z-scan2 fluorescence correlation
spectroscopy. Increased content of both, cholesterol and peptide reduced lipid diffusion
rates. Decrease in lipid mobility is probably caused by several effects such as changes
in bilayer thickness due to cholesterol presence3, membrane crowding4 or lipid-peptide
interaction. We are currently investigating the impact of the latter two effects.
References:
de Planque, M.R.R.; Killian, J.A.: Molecular membrane biology. 2003, 20, 271-84.
2
Benda, A.; Beneš, M.; Mareček, V.; Lhotský, A.; Hermens, W. Th.; Hof, M.: Langmuir.
2003, 91, 4120-6.
3
Kahya, N.; Schwille, P.: Journal of fluorescence. 2006, 16, 671-8.
4
Ramadurai, S.; Holt, A.; Krasnikov, V.; van den Bogaart, G.; Killian, J.A.; Poolman, B.:
Journal of the American Chemical Society. 2009, 131, 12650-6.
1
CHARACTERIZATION
OF BIOLOGICAL MEMBRANE
Mgr. Martina Parisová
Assoc. Prof. Dr. Ing. Tomáš Navrátil
Biological membranes are very complex structures which separate intracellular space of
cells from external space and ensure different processes important for life of cells.
Because real biological membranes are very complicated, suitable model systems with
similar properties have been i ntroduced (e.g., [1, 2]). For these purposes, large
unilamellar liposomes (LUVs) have been used. Biological membranes are formed from
amphipathic molecules – phospholipids. Composition of liposomes is very similar to
biological membranes, because their basic structure is formed from phospholipids too.
This is one of the reasons why liposomes are used as models of artificial cell
membranes. This contribution deals with preparation and with characterization of
artificial liposomes. They can be used for investigation of heavy metal transport across
biological membranes [3, 4]. Liposomes were prepared by a hydration method and their
properties in presence and absence of cadmium ions were studied voltammetrically by
glassy carbon electrode. Size of liposomes was determined using dynamic light
scattering.
References
1. M. Parisova, T. Navratil, I. Sestakova, J. Jaklova Dytrtova, and V. Marecek,
International Journal of Electrochemical Science, 8 (2012) 27
2. T. Navratil, I. Sestakova, and V. Marecek, International Journal of Energy and
Environment, 5 (2011) 337
3. Y. F. Hsieh, T. L. Chen, Y. T. Wang, J. H. Chang, and H. M. Chang, Journal of Food
Science, 67 (2002) 2808
4. J. S. Dua, Rana, A. C., Bhandari, A. K.,, Interantional Journal of Pharmaceutical
Studies and Research, 3 (2012) 14
Acknowledgments
The research was supported by GA CR (project No. P208/12/1645).
MESOPOROUS MOLECULAR SIEVES:
MATERIALS FOR HETEROGENEOUS
METATHESIS CATALYSTS AS WELL AS CO2
ADSORPTION
Mgr. Jakub Pastva
RNDr. Hynek Balcar, CSc., Ing. Arnošt Zukal, CSc.
Siliceous mesoporous molecular sieves are relatively new material with regular
structures, high surface areas (even more than 1000 m2/g), high void volumes (up to
1.5 cm3/g), and pore size in mesoporous region (diameter from 2 nm to 50 nm) with
narrow pore size distribution. Due to these exceptional properties, mesoporous sieves
have great potential in many catalysis, separation and adsorption1. Olefin metathesis
has become a powerful tool in organic synthesis and is now extremely useful having
numerous applications in fine chemical synthesis. In adsorption field, control of the CO2
emission has become serious and challenging topic. One of the options for the removal
of CO2 is adsorption on s uitable solid adsorbents. Among the large number of such
materials, mesoporous magnesium oxide has been studied as a plausible adsorbent for
carbon dioxide mainly because of its lower energy requirement for regeneration.
Heterogeneous catalysts have been pr epared by immobilization of commercial
Hoveyda-Grubbs 1st generation catalyst on siliceous mesoporous molecular sieve of
different pore size and architecture modified with linkers containing
dicyclohexylphosphine (PCy2) groups. These catalysts show low Ru leaching and c an
be used repeatedly. Activity of the catalysts was tested in the ring closing metathesis of
various substrates 2.
Magnesia–alumina have been applied for the pillaring of the layered precursor of zeolite
MCM-22. Calcination of pillared materials has led to new varieties of MCM-36 type
zeolite. The carbon dioxide isotherms on prepared samples reveal that their adsorption
properties are decisively influenced by the type of pillaring agent used. The comparison
of starting MCM-22, siliceous MCM-36 and modified samples
MCM36/MgO.Al2O3 (A) and (B) has shown that impregnation of MgO into the pillars of MCM36 enhances adsorption capacity in the region of equilibrium pressures lower than 10
kPa due to the strong interaction of CO2 molecules with MgO.
References:
A. Zukal, J. Pastva, J. Čejka, Microporous and Mesoporous Materials 2013, 167,
44-50.
2
J. Pastva, J. Čejka, N. Žilková, O. Mestek, M. Rangus, H. Balcar, J. Mol. Catal. A:
Chem., submitted.
1
TOWARDS ACCURATE AB INITIO
SIMULATIONS OF FLUORESCENT
PROBES
Bc. Marek Pederzoli, MSc
Mgr. Jiří Pittner Dr. rer. nat., DSc.
The use of fluorescent probes in biochemical and bi ophysical research is very well
established and the number of their applications is constantly growing due to their high
versatility, sensitivity and quantitative capabilities. Among many other uses, fluorescent
probes are employed for localization of biomolecules in cellular systems, monitoring
transport of molecules through membranes, identifying conformational changes of
proteins and studying biochemical processes in vivo.
Two of the main challenges for an accurate simulation of photochemical processes
involving fluorescent probes are: i) precise calculation of the potential energy surfaces of
the probe ii) description of interactions of the fluorescent probe with a complex system
like a bio-membrane.
The potential energy surfaces of fluorescent probes are complicated by the presence of
conical intersections and avoided crossings, which enable non-radiative transitions. In
some photochemical reactions, the non-radiative transitions may even occur between
states of different spin multiplicity. These so-called inter-system crossings are usually
associated with the presence of heavy atoms, but recently they were shown to play a
dominant role even in certain light-atom molecules.
To account for inter-system crossings, the relativistic spin-orbit interaction needs to be
taken into account. We are presently implementing a method for inclusion of spin-orbit
couplings into the Newton X package in the context of Tully’s version of surface hopping
dynamics.
In order to describe the interaction of the fluorescent probe with the system, we employ
the quantum mechanics/molecular mechanics (QM/MM) method. The use of this
approach is demonstrated on the example of prodan molecule in water. The newly
developed interface of Newton X with Gromacs will enable us to perform simulations of
fluorescent probes in bio-membranes.
References:
Barbatti, M.; Granucci, G.; Persico, M.; Ruckenbauer, M.; Vazdar, M.; Eckert-Maksic, M.;
Lischka, H J. Photochem. Photobio. A 2007,190, 228
Ruckenbauer, M.; Barbatti, M.; Muller, T.; Lischka, H. J. Phys. Chem. A 2010, 114, 6757
Richter, M; Marquetand, P.; González-Vázquez, J.; Sola, I; González L J. Chem. Theory
Comput. 2011, 7, 1253
QUENCHING OF BADAN BY
TRYPTOPHAN CAUSED BY PHOTON
INDUCED ELECTRON TRANSFER IN
MODEL MICELLAR SYSTEM
Mgr. Petr Pospíšil
Prof. Martin Hof, Dr. rer.nat. DSc.
The fluorescence environment-sensitive dyes are extensively used in the protein
science. Detection of the conformational changes, studying of the protein-protein
interaction, protein-membrane interaction and in fact, a number of biosensing
approaches are often based on following the changes in fluorescence signal of these
fluorophores. One of the classical solvatochromic probes is Badan, a relatively small
thiol-reactive Prodan analogue. This probe can be c ovalently attached to the cystein
moiety possessing a defined location within the protein scaffold.
It was proposed that Badan could be quenched by tryptophan via photoinduced electron
transfer (PET) as suggested for a l arge number of different dyes (Doose, 2009). The
implication for PET between Badan and T ryptophan has already been mentioned in
work by (Tsalkova, 2007) nevertheless, up to our knowledge no systematic study on this
issue has been published so far. We therefore decided to map the quenching
mechanism of Badan in a model micellar system containing tryptophan.
References:
Doose, S., Neuweiler, H., Sauer, M, ChemPhysChem, 2009,10, 1389–1398.
Tsalkova, T.N., Davydova, N.Y., Halpert, J.R., Biochemistry, 2007,46,106–119.
POLYMER NETWORKS DERIVED
FROM ETHYNYLPYRIDINES
Mgr. Sabina Petrášová
RNDr. Hynek Balcar, CSc.
Doc. RNDr. Jan Sedláček, Dr.
Spontaneous quaternization polymerization of ethynylpyridines (EPy) known as the
reaction yielding linear polyacetylenes [1] was modified so that the insoluble polymer
networks resulted as the products (Scheme 1). Modification consisted in the application
of bifunctional quaternizing agents of the bis(bromomethyl)arene (BBMA) type. Networks
contained polyacetylene chains substituted by pyridyl and pyridiniumyl units. The latter
units were quaternized by BBMAs that served as inter-chains linkers. Prepared networks
were found active in CO2 capture performed at near to ambient temperature. The
influence of (i) the structure of EPy and BBMA and (ii) EPy to BBMA ratio on the
properties of networks will be discussed.
N
C
CH
+ Br
CH2
Ar
CH2 Br
C
CH
CH
C
y n
x
N
+
N
Br
-
CH2
Ar
+
CH2
Br
CH
-
N
C
C
CH
x
y n
N
Scheme 1
References:
[1] Lim, K. T.; Jin, S. H.; Lee, H. J.; Park, J. W.; Kim, S. Y.; Lee, W. C.; Gal, Y.S.
Synthetic Met. 2005, 153, 301-304.
SYNTHESIS AND PROPERTIES OF
GERMANOSILICATE AND
TITANOSILICATE FORMS
OF CIT-5 ZEOLITE
Ing. Jan Přech
Prof. Ing. Jiří Čejka DrSc.
CIT-5 zeolite (IZA code: CFI) is an extra-large pore zeolite with one-dimensional 14 ring
pores. These are accessible even for bulky molecules. Therefore, with incorporation of
proper active sites, it could represent a v aluable catalyst. The CIT-5 structure was
prepared as a pure silica and w ith incorporated boron, gallium and aluminium1 but
neither as a germanosilicate and nor as titanosilicate.
CIT-5 has chains of “V” assembled 4-rings in its structure and it crystallizes into thin
plate shaped crystals. Therefore we expect it might be possible to prepare its lamellar
form in a similar way to conversion of UTL zeolite into IPC-1P.2 Germanium in the
structure (which is preferentially incorporated into 4-rings in the UTL) is crucial for this
conversion. CIT-5 titanosilicate form could represent a useful catalyst for epoxidation of
double bonds in bulky molecules used in perfumery and pharmacy.
Titanium and g ermanium containing CIT-5 structures were successfully prepared by
direct synthesis using Cab-O-Sil and titanium (IV) butoxide or germanium oxide mixtures
respectively in the presence of LiOH with N-methylspartheinium hydroxide as a structure
directing agent. Application of different ratios of silicon and titanium source led to a
group of samples with Si/Ti ratio as low as 42 (according to EDX measurement).
Germanium containing CIT-5 was prepared as pure germanosilicate and as a
germanium-aluminosilicate with initial ratio Al/Ge 1. The influence of the amount of
heteroelement on t he synthesis will be di scussed. Crystalline phases following the
formation of CIT-5 zeolite were also identified from the XRD patterns.
The catalytic activity of the titanosilicate samples was tested on selective epoxidation
reaction of 1-octene, cyclooctene and α-pinene with hydrogen peroxide as an oxidant.
The results were compared with standard TS-1 zeolite.
References:
1. Yoshikawa, M.; Wagner, P.; Lovallo, M.; Tsuji, K.; Takewaki, T.; Chen, C.; Beck, L.W.;
Jones, C.; Tsapatsis, M.; Zones, S.I.; Davis, M.E. J. Phys. Chem. B 1998, 102, 71397147.
2. Roth, W.J.; Shvets, O.V.; Shamzhy, M.; Chlubná, P.; Kubů, M.; Nachtigall, P.; Čejka,
J. J. Am. Chem. Soc. 2011, 133, 6130-6133.
NOVÁ SKUPINA
FUNKČNÍCH MOLEKULÁRNÍCH
STRUKTUR NA BÁZI CARBORANTHIOLŮ
Martin Rajmon
RNDr. Zdeněk Bastl, CSc.
Molekulární uspořádané vrstvy na površích kovů jsou zajímavou a prakticky důležitou oblastí
výzkumu vzhledem k jejich uplatnění v chemickém průmyslu, medicíně, v mikroelektronice,
při zhotovení biokompatibilních materiálů, biosenzorů, jejich potenciálnímu využití pro
distribuci lečiv v živých organismech aj. Nejvíce zkoumanými a využívanými strukturami v
oblasti povrchových molekulárních uspořádaných vrstev jsou lineární alkylthioly vázané
nejčastěji k povrchu zlata. Jejich nevýhodou je však m.j. jejich nestabilita spočívající v
postupné degradaci při expozici na vzduchu.
Cílem tohoto příspěvku je představit nové, stabilnější a perspektivní uspořádané molekulární
vrstvy na bázi thiolů karboranů a jejich derivátů chemisorbovaných na površích zlata a stříbra.
V příspěvku jsou uvedeny příprava a výsledky studia stability a čistoty výchozích povrchů
zlatých vrstev připravených metodou PVD a použitých pro imobilizaci molekul, příprava
uspořádaných molekulárních vrstev sloučenin 1-SH-1,12-C2B10H11, 1-SH-12-COOH-1,12C2B10H10 , 2-(SH)2-1,2-C2B10H10 a 9,12-(SH)2-1,2-C2B10H10 adsorpcí z roztoku a výsledky
jejich charakterizace metodou fotoelektronové spektroskopie. Byla měřena a numericky
zpracována fotoelektronová spektra S 2p, B 1s, C 1s, O 1s a Au 4f (Ag 3d) fotoelektronů. Ze
spekter byla vypočítána stechiometrie povrchových vrstev a určen způsob vazby molekul k
povrchu kovu. Získané výsledky jsou důležité pro optimalizaci podmínek přípravy těchto
vrstev.
[1]
A. S. Duwez, Exploiting electron spectroscopies to probe the structure and
organization of self-assembled monolayers: a review, J. Electron Spectroscopy
Relat.Phenom, 2004, 97-138.
[2]
J. N. Hohman, S. A. Claridge, M. Kim, P. S. Weiss, Cage molecules for self-assembly,
Materials Science and Engineering R 70, 2010, 188-208.
MODIFIED SILICATE GELS FOR THE
CONSOLIDATION OF WEATHERED
HISTORICAL MATERIALS
M.Sc. Monika Remzová
Ing. Jiří Rathouský, CSc.
Silicon alkoxides, such as silicon ethoxide or its oligomers are excellent consolidants for
the weathered silicate materials. Their soft point is the cracking of formed gels due to the
syneresis and residual drying stress leading to their decreased mechanical strength, and
certain incompatibility of their physical properties with those of the stone.
The shrinkage and cracking of the gel can be reduced by the formation of mesopores
within the gels or by the modification with particles. Mesopores could be created by
adding a t emplate, such as amphiphilic polymers or other surfactants, to the sol and
removing it after the rigid mineral structure has been formed. By adding particles of
oxides to the alkoxide sols composites are formed after the hydrolysis and
polymerization, which exhibit microstructure of particulate systems and are distinct from
the polymeric gels without particles.
We have aimed at two systems, namely at particle and particle-pore modified gels. Both
approaches have provided materials with improved mechanical properties. Cracking of
layers about 5mm in thickness due to drying is reduced owing to the presence of
nanoparticles 10 to 20 nm in size. The polymers or surfactants added to the sol improve
the elasticity of the formed gel which also reduced cracking. After their removal
mesopores are formed. The physical properties of the modified gels are therefore much
closer to those of the historical materials in comparison with purely polymeric nonporous gels.
VÝVOJ METOD EXTRAKCE TĚKAVÝCH LÁTEK
Z BIOLOGICKÝCH VZORKŮ
Bc. Michaela Rybárová
Prof. RNDr. ŠPANĚL Patrik, Dr. rer. nat.
Poměrně novou a atraktivní metodou klinické diagnostiky je analýza dechu. Její
výhody spočívají zejména v neinvazivnosti metody. Podstatou analýzy dechu je
kvantifikace metabolitů v dechu, jenž mohou indikovat určitá onemocnění. Jelikož se
tyto metabolity vyskytují v koncentracích v řádech ppm (a menších), lze je
analyzovat pouze nejmodernějšími analytickými metodami, jako je například SIFTMS (Selected ion flow tube mass spectrometry, respektive hmotnostní spektrometrie
v proudové trubici s vybranými ionty). Optimálně by se měl dech analyzovat pomocí
SIFT-MS v reálném čase, avšak ne vždy je to možné. Cílem tohoto experimentu je
proto vyvinout metodu a zařízení pro odběr biologického vzorku tak, aby jej bylo
možné analyzovat později v laboratoři.
Během laboratorního výzkumu byl zvolen sorbent vhodný pro metodu odběru vzorku
dechu a jeho pozdější analýzu. Sorbent byl vložen do tzv. sorpční trubičky, která je
určena k odběru plynných biologických vzorků pomocí čerpadla. Prostřednictvím
vhodně zvoleného sorbentu dojde k zachycení zkoumaných analytů na trubičce.
Analyt je dále ze sorpční trubičky uvolněn, v tomto případě pomocí termální
desorpce, a analyzován metodou SIFT-MS. Mezi zkoumané sorbenty byly zvoleny tři
druhy sorbentů - polymerní sorbent Tenax TA a uhl íkaté sorbenty Carbopack C a
aktivní uhlí.
PURIFICATION
AND CHARACTERIZATION
OF SINGLE WALL
CARBON NANOTUBES
Ana Santidrián García
RNDr. Ing. Martin KALBÁČ, Ph.D.
As prepared carbon nanotubes (CNTs) are usually accompanied by carbonaceous or
metallic impurities, so purification is essential. Recent studies showed that steam is able
to remove the amorphous carbon and the graphitic shells coating the metal particles
present in as-made CNTs without changing the tubular structure or inducing defects or
functional groups. Steam is also used to open and shorter carbon nanotubes. We use
steam purification following the process by Thermogravimetric analysis. Our efforts are
focus on t he improvement of this technique looking for the optimizing set up and
conditions.
As well as steam purification, it was shown that magnetic filtration followed by oxidation
is a pow erful tool for purification. Our idea is to combine the steam purification and
magnetic filtration to obtain a reduction in the ferromagnetic catalyst content, to remove
amorphous carbon and graphitic particles without damaging the structure of carbon
nanotubes.
Spectroscopy (Near Infrared, Raman), Raman Spectroelectrochemistry, and
Thermogravimetric Analysis were used to analyze samples, mainly to evaluate
purification steps, trying to analyze the different diameter distribution in the steps and the
defects present in the CNTs samples.
References:
Tobias G., Shao L. Salzmann G. C., Huh Y., Green M. L.H., J Phys Chem B 2006, 110,
22318-22322.
Ballesteros B., Tobias G. Saho L., Pellicer E., Nogués J., Mendoza E., Green M. L.H.,
Small 2008, 4, 1501-1506.
Kim Y., Luzzi, D.E., J Phys Chem B 2005, 109, 16636-16643.
RUTHENIUM CATALYSTS FOR
METATHESIS AND ETHENOLYSIS OF
CARDANOL
Tushar Shinde
RNDr. Balcar Hynek, CSc.
The Ru - alkylidene complexes (Grubbs and Hoveyda-Grubbs catalysts) belong to
the most active and frequently used metathesis catalysts. Their high tolerance to the
heteroatoms in substrate molecules made them an important tool in organic
synthesis.[1]
The aim of this contribution is to report the application of Ru catalysts {1 and 1
immobilized on SBA-15 (d = 6.8 nm)}, in metathesis of cardanol. Cardanol is the
phenolic substrate which can be obtained by decarboxylation of anacardic acid, the
main component of Cashew Nut Shell Liquid (CNSL). Cardanol is worth to study
because firstly it’s a natural product (i.e. renewable source of chemicals) and
secondly CNSL are produced in large quantity but it is little known about chemical
transformation of cardanol by metathesis. The given catalysts have proved to be
active in cardanol metathesis even without protecting OH groups. Cardanol
ethenolysis (cross metathesis with ethylene) proceeded with nearly 100% conversion
with high selectivity under mild conditions (room temperature and 3 bar ethylene
pressure).
OH
N
MW = 302
OH
OH
N
Cl
Cl
Ru
O
O
S
N
MW = 408
O
MW = 196
1
Zhan catalyst
As the catalyst 1 was attached to the sieve surface by non-covalent interactions, the
Ru leaching depends on the polarity of solvent as well as substrate used in the
reaction. [2] The Ru leaching was found for ethenolysis of cardanol in toluene (2.5 %
with respect to the original content of Ru).
References:
1. R. Grubbs, Angew. Chem. Int. Ed., 2006, 45, 3760-3765.
2. Balcar H.,Shinde T., Žilková N., Bastl Z., Beilstein J. Org. Chem. 2011, 7, 22–28.
INTERACTION OF QUANTUM DOTS WITH
ORGANIC MOLECULES
Ing. Jan Suchánek
Doc. Ing. Zdeněk Zelinger, CSc.
Quantum dots (QD's) are fluorescent nanoparticles with many useful size dependent
properties. The most known QD's are semiconductor nanocrystals (e.g. CdS, CdSe) [1].
The very interesting QDs based on other materials (carbon, boron nitride QD's) were
reported recently [2, 3]. The interaction of these nanoparticles with organic dyes has
large impact to different fields like photovoltaics, bioimaging, photodynamic therapy
(PDT) and sensors.
The studies of the formation of self-assemblies between CdSe 520 (~2,5 nm) quantum
dots (QD's) and Zn phthalocyanines (Pc) and azaphthalocyanines (AzaPc), respectively
were an ai m of my previous work. T he photophysical properties of these assemblies
were studied using both steady-state and time-resolved luminescence/absorption
spectroscopy. The formation of the self-assemblies was accompanied by a blue shift of
the Q - band of the dyes and by quenching of the CdSe QDs luminescence.
This work is focused on the interaction of differently sized CdSe (CdSe 520, size ~ 2,5
nm and CdSe 640, size ~ 6,5 nm) quantum dots with Pc and AzaPc, respectively. The
comparison of both studies provided a controlled spectral analysis. A selection of
different sizes of QDs allowed t uning of the spectral overlap between CdSe QD's
luminescence and dye absorption. Any Forster resonance energy transfer to the dye
wasn't observed, in spite of the luminescence emission of CdSe 640 matches the Qbands of studied Pc's and t he luminescence of CdSe 640 was quenched upon
interaction. The quenching mechanism was atributed to the photoinduced electron
transfer between CdSe and Pc.
The further studies were targeted the comparison of semiconductor QD's with new class
of QD's – graphene quantum dots (GQD). The interaction of GQD with porphyrins is
studied by absorption and luminescence spectroscopy. Small bathochromic shift of the
Soret band of TMPyP porphyrin and quenching of fluorescence lifetime of TMPyP
porphyrin were observed.
References:
[1] T. Trindade, P. O'Brien, N.L. Pickett, Chemistry of Materials, 13 (2001) 3843-3858.
[2] S.N. Baker, G.A. Baker, Angewandte Chemie - International Edition, 49 (2010) 6726-6744.
[3] S. Zhu, S. Tang, J. Zhang, B. Yang, Chemical Communications, 48 (2012) 4527-4539.
STUDY OF DIRADICALS BY EXPLICITLY
CORRELATED MULTIREFERENCE
COUPLED CLUSTER METHODS
Bc. Matej Švaňa
One of the most often used approaches of computational chemistry nowadays is the
single reference coupled cluster (CC). In specific, the coupled cluster singles doubles
(CCSD) method has found a w idespread use for its well balanced ratio between cost
and accuracy. Nowadays, also the pertubative triples coupled cluster method (CCSD(T))
Is gaining popularity.
There are cases, however, where the single-determinantal approach does not perform
so excellently. Examples include open-shell systems such as carbenes, transition metal
atoms, biradicals and excited states in general. The difficulties arise because of the
degeneracy or quasi-degeneracy of the reference Slater determinants.
One of the possible cures to tackle these complications is to use the multi reference
(MR) methods. These, however, introduce a new level of complexity into the
calculations. In order to lower the computational cost of such an approach, explicit
correlation (the F12 methods) is used.
In my lecture, I will be t alking about the multireference Brillouil-Wigner coupled cluster
method with perturbative triples and explicit correlation (MR BWCCSD(T)-F12), which is
being developed in our group.
I will focus on t he results of calculations performed on the Bergmann reaction, with a
possibility of discussing one another biradical system.
References:
S. Kedžuch, O. Demel, J. Pittner, and J. Noga, in Recent Progress in Coupled Cluster
Methods, edited by P. Čársky, J. Paldus, and J. Pittner (Springer, Berlin, 2010), pp.
251–266
OVERTONOVÁ SPEKTROSKOPIE
V SUPERSONICKÝCH EXPANZÍCH
Vít Svoboda
Mgr. Ondřej Votava PhD.
Spektroskopie s vysokým rozlišením v plynné fázi je vhodnou experimentální technikou
umožňující studium vibračně-rotačních stavů molekul. Pomocí této techniky je například
možné studovat zemskou atmosféru, ale i atmosféry planet Sluneční soustavy. Vibrační
spektra molekul za pokojové teploty dosahují značné složitosti díky populaci vyšších
rotačních stavů. Při použití expanze plynu supersonickou tryskou do vakua dochází
k výraznému ochlazení molekul, což vede ke zjednodušení měřených spekter.
Cílem práce je studium overtonových a kombinačních vibračních pásů N-H vazeb
amoniaku v blízké infračervené oblasti pomocí vysoce rozlišené absorpční
spektroskopie, konkrétně v oblasti 6600-6900 cm-1. Pomocí spektrálních metod byly
nejdříve charakterizovány podmínky expanze a následně byly identifikovány spektrální
linie s nízkým rotačním kvantovým číslem J s využitím dvouteplotní analýzy pro
empirické přiřazení rotačních kvantových čísel. Je diskutován vliv nukleární spinové
statistiky na populaci rotačních stavů a na charakter měřených spekter. Bude
diskutována souvislost práce s teoretickými předpověďmi spekter [1] a s nejaktuálnější
publikovanou experimentální prací [2]. Součástí práce je kromě spektroskopických
měření i vývoj a charakterizace používaných laserů, konkrétně SAF (Single Angled
Facet) laserových čipů umožňujících přeladění přes širokou spektrální oblast 450 cm-1.
Reference:
[1] S. N. Yurchenko, Journal of Molecular Spectroscopy, 2011, 268, 123–129.
[2] K. Sung, L. R. Brown, JQSRT, 2012, 113, 1066–1083.
CHLOROBENZENE MASS SPECTRA,
PHOTODISSOCIATION DYNAMICS
Mgr. Pavla Svrčková
Mgr. Michal Fárník Ph.D. DSc.
Chlorobenzene is one of the molecules, which is located in atmosphere and it assists
in creating the ozone hole. The gas acts as a s ource of ClO, which helps in the
breakdown of stratospheric ozone. Therefore understanding chlorobenzene
photochemistry is essential for overall understanding of the processes in the stratospher.
We carried out an initial exploratory measurements of the chlorobenzene and mixed
chlorobenzene-water clusters. Chlorobenzene in a r eservoir in the source chamber is
heated and expanded in a carrier gas (He, Ar) through a nozzle into a vacuum. The
generated clusters are electron ionized and detected by a e reflectron time-of-flight
(RTOF) mass spectrometer [1].
In the next stage, we examine the photodissociation dynamics of chlorobenzene using
velocity map imaging method [2]. This method is very convenient because the images of
photofragments contain the complete information about the kinetic energy and angular
distribution.
Acknowledgement: Grant No. 203-09-0422
References:
[1] J. Kočišek, J. Lengyel, and M. Fárník, J. Chem. Phys. 138, 124306 (2013)
[2] Whitaker, B., Imaging in Molecular Dynamics, 2003, ISBN 978-0-521-81059-3
SYNTÉZA KOMPLEXŮ PRVKŮ
4. SKUPINY S CYKLOPENTADIENYLKETIMIDOVÝMI CHELATUJÍCÍMI
LIGANDY
Miloš Večeřa
RNDr. Martin Lamač, Ph.D.
Koordinační sloučeniny prvků 4. skupiny s cyklopentadienylem (Cp) jakožto η5ligandem byly v minulosti intenzivně studovány jako katalyzátory pro polymeraci
olefinů.1 Byly připraveny různě modifikované tzv. sendvičové i polosendvičové
komplexy (tj. s jedním či dvěma Cp ligandy). Příkladem jsou tzv. CGC (constrained
geometry complex) komplexy, jež mají na Cp připojen substituent nesoucí nejčastěji
amidovou funkční skupinu, která je také vázána na kovové centrum. Tyto komplexy
se ukázaly jako vynikající katalyzátory kopolymerací ethylenu s α-olefiny s vysokou
aktivitou, která bývá vysvětlována výrazným obnažením aktivního centra díky
geometrii uvedených ligandů.2 Obdobně jsou pro polymerace zajímavé i komplexy
kombinující Cp a ketimidové ligandy.3
V naší práci se věnujeme přípravě sendvičových a polosendvičových komplexů
s hybridními Cp-ketimidovými ligandy. Vycházíme z námi dříve připravené lithné soli
Cp s pendantní nitrilovou skupinou, na které provádíme alkylaci. Produktem je
dilithná sůl, která s příslušnými kovovými prekurzory poskytuje metalocenové
komplexy. Ty poté charakterizujeme spektrálními nebo difrakčními metodami a
studujeme jejich katalytické vlastnosti a reakce s Lewisovými či Brønstedovými
kyselinami.
Ti
Cl
N
Cl
tBu
HCl
Et3N
Ti
Cl
Cl
NH
tBu
Cl
Reference:
1
(a) McKnight, A. L.; Waymouth, R. M. Chem. Rev. 1998, 98, 2587; (b) Britovsek,
G. J. P.; Gibson, V. C.; Wass, D. F. Angew. Chem. Int. Ed. 1999, 38, 428; (c)
Gibson, V. C.; Spitzmesser, S. K. Chem. Rev. 2003, 103, 283.
2
Braunschweig, H.; Breitling, F. M. Coord. Chem. Rev. 2006, 250, 2691.
(a) Nomura, K; Liu, J. Dalton Trans. 2011, 40, 7666; (b) Nomura, K. Dalton Trans.
2009, 8811; (c) Ferreira, M. J.; Martins, A. M. Coord. Chem. Rev. 2006, 250, 118.
3
AB INITIO VIBRATIONAL TRANSITION
CALCULATION BY THE NOMO/CI METHOD
ON A SIMULATED QUANTUM COMPUTER
Ing. Mgr. Jakub Višňák
Ab initio quantum chemical calculations of molecular properties done on classical
computers demand large computation resources (time, memory). For the full
configuration interaction (FCI), which gives the most precise results within given set of
molecular orbitals (and which is the only truly reliable method in many cases),
computational resources scale exponentially with the number of molecular orbitals (size
of the molecule). Quantum computers are able to give the same results in polynomial
time [1]. In other words – quantum computers can simulate quantum systems efficiently
[2].
For the vibrational transitions computation the above mentioned reduction of asymptotic
complexity of quantum (full) configuration interaction (QCI as algorithm for quantum
computer), when compared to FCI calculation (done on classical computer), calls for
NOMO/CI method (which treats electrons and nuclei explicitly on equal footing and goes
beyond the adiabatic approximation [3]). In this way, vibrational states are obtained
directly, rather than by introducing the potential energy surface(s) and s ubsequenty
performing a nuclear-motion calculation.
The lecture presents results of NOMO/CI hamiltonian eigenvalue estimation by the
Iterative Phase Estimation Algorithm (IPEA, part of the QCI [4]), simulated on a classical
computer, as a demonstration of possibility to directly compute energy of rotationless
vibrational 0-1 transition in several isotopomers of the hydrogen molecule (H2, HD, HT,
…) on (future) quantum computers.
References:
[1] Abrams, D. S.; Lloyd, S. Phys.Rev.Lett. 1999, 83, 5162-5165.
[2] Feynmann R. P.: Simulating Physics with Computers, International Journal of
Theoretical Physics 1982, Vol. 21, Nos. 6/7.
[3] H. Nakai, “Nuclear Orbital plus Molecular Orbital (NOMO) Theory: Simultaneous
Determination of Nuclear and Electronic Wave Functions without Born-Oppenheimer
Approximation,” Int. J. Quant. Chem. 2007, 107, 2849-2869.
[4] Dobšíček, M.; Johansson, G.; Shumeiko, V.; Wendin, G. Phys. Rev. A 2007, 76,
030306.
ELEKTROCHEMICKÝ SENZOR
S ELEKTRODOU MODIFIKOVANOU
POLYMERNÍ METHYLENOVOU MODŘÍ PRO
STANOVENÍ SULFANU
Mgr. Magda Zlámalová
Sulfan, plyn známý pro svou vysokou toxicitu, je v posledních letech zkoumán jako
přirozená endogenní látka se slibnými terapeutickými účinky [1]. Velmi nízká fyziologická
koncentrace sulfanu i potencionální terapeutická koncentrace si žádají vývoj
vhodnějších analytických metod s důrazem na jejich citlivost a selektivitu.
Ke stanovení sulfanu jsou v poslední době hojně vyvíjeny metody využívající elektrod
modifikovaných vhodným redoxním mediátorem, jež řeší problémy čistých pevných
elektrod, jako jsou nízká citlivost, pomalý přenos elektronů, nízká elektrokatalytická
aktivita, oscilace proudů či nutnost vysokého přepětí na elektrodě.
Fenothiazinové barvivo methylenová modř je využívána nejen ve spektrometrickém
stanovení sulfidů, ale v posledních letech právě jako mediátor elektronového přenosu v
elektrochemii [2].
Elektropolymerizací methylenové modři vzniká na povrchu pevných elektrod vodivý
polymerní film vykazující elektrokatalytickou aktivitu při oxidaci sulfidů, thiolů a dalších
sirných sloučenin [3]. Díky silné adhezi polymeru k elektrodovému povrchu je film
stabilní rovněž v široké škále pH [4].
Práce prezentuje studii vrstvy polymerní methylenové modři a elektrochemickou detekci
sulfidových aniontů ve vodném prostředí metodou cyklické voltametrie na elektrodě,
která je tvořená bazální rovinou vysoce orientovaného pyrolytického grafitu (HOPG)
modifikovanou polymerní methylenovou modří.
Reference:
[1] Predmore, B.J.; Lefer, D.J.; Gojon,G.: Antioxid. Redox Sign. 2012, 17, 119-140
[2] Karyakin; A.A.; Strakhova; A.K.; Karyakina; E.E.; Varfolomeyev; S.D.;
Yatsimirsky A.K.: Bioelectrochem. Bioenerg. 1993, 32, 35-43
[3] Marinho; M.I.C.; Cabral M.F.; Mazo L.H."; M.I.C.; Cabral M.F.; Mazo L.H.:
J. Electroanal. Chem. 2012, 685, 8-14
[4] Liu, J.; Mu, S.: Synthetic Mat. 1999, 107, 159-165
THE TOXICITY OF SILVER
NANOPARTICLES TO SCENEDESMUS
QUADRICAUDA AND CHLORELLA
VULGARIS
Radek Žouželka, M.Sc.
INg. Jiří Rathouský, CSc.
Silver nanoparticles were prepared via reduction of [Ag(NH3)2] cation by various
saccharides or by sodium borohydride. Three monosaccharides (glucose, galactose and
xylose) and t wo disaccharides (maltose and lactose) were used. The syntheses
produced very small particles about 5-100 nm in size with narrow size distributions. The
use of disaccharides yields smaller particles than using monosaccharides. The smallest
silver nanoparticles with an av erage size of 5 nm with a nar row size distribution as
determined by DLS were prepared using sodium borohydride. The maximum of the UVVIS absorption spectrum depends on the particle size; being red shifted with increasing
particles size.
The smallest nanoparticles of about 5 nm exhibit the highest toxicity to algae
Scenedesmus quadricouda and Chlorella vulgaris, EC 50 being 1 mg/L. The toxicity of
the 5 nm particles to S. quadricauda is even higher than that of silver cations at the
same concentration. C. vulgaris is more vulnerable than S. quadricauda and is
effectively killed by substantially larger particles (40-100 nm) at low concentration of
about 2-4 mg/L.The toxicity of silver nanoparticles can be associated with their size and
their oxidation to the silver ions. For S. quadricauda there is a linear correlation between
the size of nanoparticles and their biocidal efficiency. Testing the biocidal performance
was carried out at the Department of Water Technology and Environmental Engineering
of the Institute of Chemical Technology Prague.
Poznámka/Note
Konferenční centrum v Liblicích u Mělníka
24.-26.4.2013

seminář studentů 2009 - J. Heyrovský Institute of Physical Chemistry

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